The apparatus and method of the invention are particularly appropriate for the separation of biological fluids comprising an aqueous component and one or more cellular components. For example, potential uses of the invention include extracting, from a volume of whole blood, a plasma component and a red blood cell component, or a platelet rich plasma component and a red blood cell component, or a plasma component, a platelet/mononuclear cell component, and a red blood cell component.
European patent application EP 1 709 983 describes a method and an apparatus for separating a volume of whole blood into at least three components in accordance with various separation protocols. For example, one protocol provides for the separation of a volume of whole blood into a plasma component, a red blood cell component, and mononuclear cell component (including a volume of plasma, platelets, mononuclear cells and residual red blood cells). The apparatus comprises a centrifuge adapted to cooperate with various bag sets, including a bag set comprising an annular separation bag, which is connected to three satellites bags, including a bag for plasma, a bag for a mononuclear cell component, and a bag for a red blood cell component bag. The centrifuge includes a rotor for spinning the separation bag and centrifuging the whole blood contained therein, the rotor having a turntable for supporting the separation bag and a central compartment for containing the component bags connected to the separation bag; and a squeezing system for squeezing the separation bag and causing the transfer of at least a plasma component into the plasma component bag and a mononuclear cell component into the mononuclear cell component bag.
According to European patent application EP 1 709 983, a method for separating a volume of whole blood contained in a separation bag into at least three components comprises the steps of centrifuging the separation bag so as to separate therein a first inner layer comprising plasma, a second intermediate layer comprising platelets, a third intermediate layer comprising lymphocytes, monocytes and granulocytes and a fourth outer layer comprising red blood cells, wherein at least the third and fourth layers partially overlap; transferring, into a plasma component bag connected to the separation bag, a plasma component substantially comprising a first fraction of the first layer; and transferring, into a mononuclear cell component bag connected to the separation bag, a mononuclear cell component comprising at least a fraction of the third layer comprising lymphocytes and monocytes.
This method allows for the separation of a red blood cell component substantially devoid of mononuclear cells, which for various reasons are undesirable in transfusible red blood cells.
White blood cells are not the only contaminant that it is desirable to remove at least partially from a red blood cell component in which red blood cells are packed into a residual volume of plasma that may contain undesirable proteins (e.g. prions) and viruses.